1 files changed, 52 insertions, 0 deletions
diff --git a/python/mach/mach/mixin/logging.py b/python/mach/mach/mixin/logging.py
new file mode 100644
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+++ b/python/mach/mach/mixin/logging.py
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+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import logging
+
+
+class LoggingMixin(object):
+    """Provides functionality to control logging."""
+
+    def populate_logger(self, name=None):
+        """Ensure this class instance has a logger associated with it.
+
+        Users of this mixin that call log() will need to ensure self._logger is
+        a logging.Logger instance before they call log(). This function ensures
+        self._logger is defined by populating it if it isn't.
+        """
+        if hasattr(self, "_logger"):
+            return
+
+        if name is None:
+            name = ".".join([self.__module__, self.__class__.__name__])
+
+        self._logger = logging.getLogger(name)
+
+    def log(self, level, action, params, format_str):
+        """Log a structured log event.
+
+        A structured log event consists of a logging level, a string action, a
+        dictionary of attributes, and a formatting string.
+
+        The logging level is one of the logging.* constants, such as
+        logging.INFO.
+
+        The action string is essentially the enumeration of the event. Each
+        different type of logged event should have a different action.
+
+        The params dict is the metadata constituting the logged event.
+
+        The formatting string is used to convert the structured message back to
+        human-readable format. Conversion back to human-readable form is
+        performed by calling format() on this string, feeding into it the dict
+        of attributes constituting the event.
+
+        Example Usage:
+
+        .. code-block:: python
+
+            self.log(logging.DEBUG, 'login', {'username': 'johndoe'},
+                'User login: {username}')
+        """
+        self._logger.log(level, format_str, extra={"action": action, "params": params})